Grinding apparatus



Dec. 2, 1947.

J. A. ELME S GRINDING APPARATUS Fil ed Nov. 21, 1945 Fig. 1.

2 Sheets-Sheet 1 ATTORNEY Dec. 2 1947.

Filed NOV. 21, 1945 Fig. 3.

2 Sheets-Sheet 2 INVENTOR J0/7WA.LM6

ATTORNEY :a. work piece in operative relation thereto, and

Patented Dec. 2, 1947 UNITED STATES ap- GRINDING APPARATUS JohnA. Elmes Beaver Falls,- Pa.,.-ass i gnornto Walter ,L. .Ryan, Pittsburgh, Ba.

' Application November 21, 1945,--Serial j-No. j630,0 13

One object of my invention is to provide appavratus of suchform that the surfaces of articles .of uneven or non-uniform contour can-be efficiently ground and polished throughout allztheir exposed areas.

Another object of v.my invention'isto provide apparatus of such formrthat an abrasive belt can -readily be caused to present either a convex or a concave surfacingzone for engagement with-arti cles being operated upon.

Still another object of my invention is to provide grinding and polishing apparatus of simple form which can readily be employed in the .ac-

curate and expeditious surfacingof curved surfaces of varying radii.

A further object of my invention is to provide;

- an improved method of surfacing articles whereby a single abrasive belt may be employedto rough-grind an article as well as to give-a smoother finish thereto.

Some of the formswhich my invention may take are shown in the accompanyingdrawings wherein Figure 1 is a view of a grinding machine in side elevation; Fig. 2 is a fragmentary plan view of the back-up roll of Fig. 1, with a belt and Fig. 3 is a side view showing a modification ofthe machine of Fig. 1.

The apparatus comprises a stand 4 upon which is mounted a motor 5 having a driving pulley-li for an abrasive belt 1. --A-stand 8 is provided for idler pulleys 9 and I that-support and guide the belt 1, A back-up roll -I l is journaled in abracket 12 that is pivotally supported at I3 upon'the stand 8. The bracket has aslotM through which a clamping screw extends and has threaded engagement with thestand 8, whereby the bracket l2 can be set at various adjusted positions around its pivot 13. The back-up r011 H may be of metal and may be faced with rubber or other suitable non-metallic material, when desired.

The pulley 9 is supported by a bracket l6 which is journaled on the frame, on a vertical axis as indicated at H. An adjusting screw l8 has threaded engagement with a swivel nut l9 that is carried by the stand, and has rotatable connection at with the bracket l6, so that when the handle 2| of the screw [8 is turned, the angular position of the pulley 9 around its pivot I! will be changed, in order to properly guide the belt I.

'The, pulleyj his journaleddnva bracket'ZS that tis' pivotally supported-at 24, on :the stand.

-A screw 24uhaszithreaded engagement with a :swiveltnut 126.1that is carried .by :the stand, and

-.r.otatablel engagement .with. a .swiveled .pin, '21 on ithe. bracket -23. .Whenz'the handle-2.8 of the screw -:is turned,itherbracketugn Will1.be;rocked. about its .pivote24 to change'thevtension:of the.belt .1. A

. spring 29 interposedbetween thebracket and a shoulderv30: on .thewscrew .serves to. preventv chattering ofathe' bracket. ":It: will be understoodthat :the brackets.:l-2,,z l6 :an'dl23have bifurcations or arms at rthe :si'desof theirz-respective rolls so that tbothzends of. .each roll shaft. are. directly supported.

iOne-L importantffeature 10f. my.- invention .resides in the .fact.thatdttissespecially aadaptedfor what :is .called ".icontour grinding. and polishing, .;and

tozthis ;end.the .peripheral-surface of the back-up .roll -I I. will beofnon-cylindrical contour so that it will effectively polish articles of non-uniform .contourssuchas. a .handle. 32; which here constitutes the :;work ..-.pieee. The. apparatus. will .be ex- :tensively:useddnzpolishingsother articles such as -the;.:outer,..suriaces of .metallic cooking vessels ".whichfrequently:haverconsiderable curvature in generally axialndirections. :;It-. wil1be-:understood :thatflaring-surfa in eneration th wo k piece -32'swill .beiheld-:againstithe belt 1 with SllffiGient pressureztodefiect the; heltztoithe: contour of the 51011 .83 peripheralssurface.

and;may.suitably,:,cqm riseac th' t o which zthezg ta r "a ra ive ains; are:- bondedgpyau adhesive agent.

:-..Another adv nta pre ent ,in my a a us resides: in the.adiustablamonnt n .for th a -up ro l;l .-:whe ebyzitacan eisetat a point Where it will deflect the belt to a greater or less degree than shown in Fig. 1, or it can be set back somewhat to a point at which it will not be engaged by the belt until a work piece is pressed against the belt. It will be seen that in the former case, there will be a lesser area of abrasive contact with a work piece, because of the convexity of the belt at the back-up roll; while in the 1atter case, the belt will be pressed to a concave shape as it passes the back-up, under the pressure of the work piece, and there will be a greater area of contact between the abrasive grains and the work piece.

One of the conditions under which the belt will be maintained convex at the grinding zone is where greater grinding force is required under a given amount of pressure or where circular articles of small circumference are to be surfaced. With the back-up roll set back sufiiciently far, there will be a partial Wrapping of the belt about the surface of the work piece with a consequently larger area of the work piece being surfaced at any given instant during rotation of the work piece by the operator. This maybe desirable where articles of large circumferences are being surfaced and where not much material is to be ground therefrom.

The apparatus can be used also in the practice of a method whereby a belt having an abrasive of a certain grit size can be used not only for rough or heavy grinding but also to give a smoother finish to an article. The back-up roll can be of cylindrical shape or have its surface contoured as indicated in Fig. 2. It has been found that if the belt has abrasive grains of 60 grit size for example, there will be a markedly different cutting effect on the work piece when applied against the belt. at points intermediate the rolls 9 and II or the'rolls Ill and l I than when the work piece is applied against the belt directly at the back-up roll. Upon application of the work piece against the belt directly at the front of the backup roll, the grit will give its normal grinding effect. However, when the work piece is applied against the beltat a point where it is not supported by-a roll, the grinding action will be less marked. For instance, with a 60grit belt, the normal 60-grit effect will be produced in a heavy grinding operation against the back-up roll, while when the work piece is moved to a point perhaps midway between the pulleys 9 and I l, the surfacing will be comparable to that produced by a 120-grit belt, thus, in effect, permitting the grinding and polishing by the use of a single belt.

Referring now to Fig. 3, I show a machine that is similar'in most part to the machine of Fig. 1, but in this case, I provide a pair of back-up rolls 34 and 35which' may, as in the case of the backup roll I I, be of cylindrical contour or have their peripheries of non-cylindrical shape.

The roll 34 is carried'by a bracket 36 that is pivotally connected to the stand 8 and is vertically-supported toward its outer end by an adjusting screw 37 which is journaled in a socket 38 that is pivotally connected to the bracket 36 and has threaded engagement with a nut 39 that is rotatably supported in a bracket arm 40, so that when the nut is turned, the roll 34 will be adjusted about its pivot 4| to move it relative to the normal path of travel of the belt I. The roll 34 is similarly adjusted by a screw 42 and its nut 43.

The rolls 34 and 35 can each be set at a different position of adjustment than the other roll, so that the belt can have different degrees of defiection at the two rolls to better suit grinding operations on articles of different size and shape. For example, articles of one size or shape can be applied against the belt at the roll 34 and articles of other size and shape can be applied against the roll 35. Also, one part of a grinding operation can be performed at the roll 34 and another part of the grinding operation can be performed by pressing the work against the belt at a point mid way between the rolls 34 and 35.

I claim as my invention:

1. The combination with a driving pulley for an abrasive belt and a support for the pulley, of

a pulley stand disposed forwardly of the support,

' pulley-supporting brackets on the stand, respectively at planes above and below the plane of the drive pulley, and projecting forwardly of the stand, guide pulleys on the brackets, in position to receive and guide the abrasive belt, means for adjusting one of the brackets about a vertical axis, to change the angularity of its pulley, means for adjusting the other bracket in a direction to affect the belt tension, a back-up member for the belt, mounted on the stand at a point intermediate the two guide pulleys, and means for adjusting the back-up member relative to the normal path of the belt between the two guide pulleys.

2. The combination with a driving pulley for an abrasive belt and a support for the pulley, of a pulley stand disposed forwardly of the support, pulley-supporting brackets on the stand, respectively at planes above and below the plane of the drive pulley, and projecting forwardly of the stand, guide pulleys on the brackets, in position to receive and guide the abrasive belt, means for adjusting one of the brackets about a vertical axis, to change the angularity of its pulley, means for adjusting the other bracket in a direction to affect the belt tension, a pair of vertically-spaced back-up rolls for the belt, mounted on the stand at points intermediate the two guide pulleys, and means for adjusting the back-up rolls vertically relative to one another and relative to the belt, to control deflection thereof from that portion of its path which is between the two guide pulleys.

JOHN A. ELMES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 294,766 Coy Mar. 11, 1884 759,995 Hodd May 17, 1904: 832,889 Wysong Oct. 9, 1906 844,366 Kitson et a1 Feb. 19, 1907 1,082,670 Wysong Dec. 30, 1913 1,167,244 Zoerner Jan. 4, 1916 1,735,903 Johnson Nov. 19, 1929 2,332,329 Maca Oct. 19, 1943 Certificate of Correction Patent No. 2,431,795. December 2, 1947. JOHN A. ELMES It is hereby certified that the name of the assignee in the above numbered patent was erroneously described and specified as Walter L. Ryan whereas said name should have been described and specified as Walter L. Ryman, as shown by the record of assignments in this Oflice; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Oifice.

Signed and sealed this 17th day of February, A. D. 1948.

THOMAS F. MURPHY,

Assistant G'ommissioner of Patents. 

